001// Copyright 2009, 2012 The Apache Software Foundation
002//
003// Licensed under the Apache License, Version 2.0 (the "License");
004// you may not use this file except in compliance with the License.
005// You may obtain a copy of the License at
006//
007//     http://www.apache.org/licenses/LICENSE-2.0
008//
009// Unless required by applicable law or agreed to in writing, software
010// distributed under the License is distributed on an "AS IS" BASIS,
011// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012// See the License for the specific language governing permissions and
013// limitations under the License.
014
015package org.apache.tapestry5.internal.services;
016
017import org.apache.tapestry5.ioc.internal.util.CollectionFactory;
018import org.apache.tapestry5.services.ComponentClasses;
019import org.apache.tapestry5.services.InvalidationEventHub;
020
021import javax.annotation.PostConstruct;
022import java.util.Map;
023
024public class StringInternerImpl implements StringInterner
025{
026    private final Map<String, String> cache = CollectionFactory.newConcurrentMap();
027
028    @PostConstruct
029    public void setupInvalidation(@ComponentClasses InvalidationEventHub hub)
030    {
031        hub.clearOnInvalidation(cache);
032    }
033
034    public String intern(String string)
035    {
036        String result = cache.get(string);
037
038        // Not yet in the cache?  Add it.
039
040        if (result == null)
041        {
042            cache.put(string, string);
043            result = string;
044        }
045
046        return result;
047    }
048
049    public String format(String format, Object... arguments)
050    {
051        return intern(String.format(format, arguments));
052    }
053}